Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
SYS.OK|MANUAL.DB● LIVE
HOMESERVICE MANUALSPONTIAC1987J2000/SUNBIRD L4-121 2.0LREPAIR AND DIAGNOSISTECHNICAL SERVICE BULLETINSALL TECHNICAL SERVICE BULLETINSA/T - 125/440 T4 SPROCKET AND FINAL DRIVE IDENTIFICATION
1987 Pontiac J2000/Sunbird L4-121 2.0L
A/T - 125/440 T4 Sprocket and Final Drive Identification
1987 Pontiac J2000/Sunbird L4-121 2.0LSECTION A/T - 125/440 T4 Sprocket and Final Drive Identification
TECHNICAL BULLETIN # 120
DATE: July 92
TRANSMISSION: 125/440 T4
SUBJECT: Drive Train Ratios
APPLICATION: GM
125/440 T4 Sprocket and Final Drive ID
If you have a car with a 125 or a 440 T4, and you're not sure that the sprockets or final drive are correct for the vehicle, you can use the Regular Production Option (RPO) label to find out.
The RPO label is a sticker that shows what options were installed on the car. Figure 1.
The RPO label is usually located on the trunk lid or the spare tire cover. Two exceptions are the Seville which is found on the left rear door jam and the Fiero which is found on the front right fender well.
Once you've found the RPO label look for a code that begins with an "F" or "G". These codes describe suspension options on the car. (Axle ratio, type of shocks, sway bars etc.) Find a code that matches one in the chart).
DATE: July 92
TRANSMISSION: 125/440 T4
SUBJECT: Drive Train Ratios
APPLICATION: GM
125/440 T4 Sprocket and Final Drive ID
If you have a car with a 125 or a 440 T4, and you're not sure that the sprockets or final drive are correct for the vehicle, you can use the Regular Production Option (RPO) label to find out.
The RPO label is a sticker that shows what options were installed on the car. Figure 1.
The RPO label is usually located on the trunk lid or the spare tire cover. Two exceptions are the Seville which is found on the left rear door jam and the Fiero which is found on the front right fender well.
Once you've found the RPO label look for a code that begins with an "F" or "G". These codes describe suspension options on the car. (Axle ratio, type of shocks, sway bars etc.) Find a code that matches one in the chart).
RENDER: 1.0x
NO RELATED
Recommended Tools & Savings
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.